Eva Hoff Wanderås MD
Recently updated 22.08.2014
Oslo University Hospital HF
Diagnostics of anal cancer
The purpose of diagnostic tests is to:
- Assess whether or not cancer is present
- Assess local and/or general extension
- Inspection of the anal region and groin
- Rectal/vaginal examination and palpation of groin
- No specific blood tests, but routine blood tests should be taken.
Endoscopy with biopsy
- Ano/proctoscopy – The anal canal is examined with an anoscope. The rectum should be simultaneously examined by proctoscopy because of differential diagnoses.
- Biopsy – Especially for perianal cancer, there may be relatively large areas with dysplasia and smaller areas with cancer. Multiple biopsies may therefore be necessary. The areas biopsied in the tumor should therefore be marked on a drawing.
- Fine-needle biopsy/cytology is performed on suspect lymph nodes in the groin and possibly using ultrasound.
- MRI of the pelvic area with groin provides the best way of assessing the extention of the tumor locally in the anal canal and in surrounding organs.
- An ultrasound examination of the anal canal may help evaluating early stage cancer.
- CT abdomen/thorax provides the best assessment for metastases.
- PET CT should be performed for accurate N and M staging. PET is not significant for T status. In a study of 61 patients, it was found that PET/PET-CT changed the stage in 23 % (15 % higher stage, 8 % lower stage) compared to CT and anorectal ultrasound. The indication for curative to palliative treatment changed in only 3 %, but in 13%, there were consequences for the size and shaping of the radiation field. PET is recommended with anal cancer greater than 2 cm.
- The TNM classification should be included in the patient journal at the conclusion of the evaluation.
- With stricturing tumors and incontinence or fistulas, a stoma may be considered to relieve symptoms before starting radiation therapy.
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